CN115676509A

CN115676509A - Method for operating a workstation of a yarn winding machine and yarn winding machine

Info

Publication number: CN115676509A
Application number: CN202210866781.7A
Authority: CN
Inventors: A·斯蒂芬; 塞巴斯蒂安·弗里茨; 杰拉尔德·屈斯特斯
Original assignee: Maschinenfabrik Rieter AG
Current assignee: Maschinenfabrik Rieter AG
Priority date: 2021-07-21
Filing date: 2022-07-21
Publication date: 2023-02-03
Also published as: JP2023017714A; EP4122858A1; DE102021118843A1

Abstract

A method for operating a station (2) of a yarn winding machine (1), comprising: rewinding the yarn (3) from the pirn (22) onto the winding drum (6) by means of the winding device (5); -defining a balloon (14) at least in the width direction by means of a balloon defining device (18); wherein the balloon defining means (18) comprise at least one balloon defining piece (23, 26) with a thread guiding surface (24, 27); rewinding a first portion of the thread (3) on the bobbin (4) onto the bobbin (6), wherein a thread withdrawal force and/or a measurement value representing the thread withdrawal force of the thread (3) is detected; when an increase in the thread withdrawal force is detected, the at least one balloon-defining member (23, 26) is switched from the rest position (R) into the operating position (A) and then a second portion of the thread (3) is rewound onto the winding drum (6). Alternatively, the distance (a 1, a 2) of the thread guide surface (24, 27) of the at least one balloon-defining element (23, 26) from the axis of rotation (25) of the spinning cylinder (4) is reduced and then a second portion of the thread (3) located on the spinning cylinder (4) is rewound onto the winding cylinder (6). Alternatively, a second balloon limiting element (26) with a second yarn guiding surface (27) is transferred from the resting position (R) into the operating position (A). In addition, a workstation (2) of a yarn winding machine (1) has a detection device (17) for detecting a yarn withdrawal force of the yarn (3) and/or a measurement value representing the yarn withdrawal force, and a control unit (13).

Description

Method for operating a workstation of a yarn winding machine and yarn winding machine

Technical Field

The invention relates to a method for operating a workstation of a yarn winding machine, wherein a yarn is rewound onto a yarn winding bobbin from a pirn with the yarn winding bobbin by means of a yarn winding device, wherein during the rewinding process a yarn balloon formed between the yarn winding bobbin and the yarn winding bobbin is defined at least in the width direction by means of a balloon defining device. The balloon defining means comprises at least one balloon defining member with a yarn guide surface. In this case, a first portion of the thread on the spinning tube is rewound onto the winding tube, wherein a thread withdrawal force of the thread and/or a measured value representing the thread withdrawal force is detected, wherein the thread guide surface is at a distance from the rotational axis of the spinning tube at least in the operating position of the balloon-limiting element or at least during the rewinding of the first portion of the thread.

The invention further relates to a method for operating a station of a yarn winding machine, wherein the balloon defining device comprises a first balloon defining member with a first yarn guide surface, wherein the first yarn guide surface of the balloon defining member has a first distance relative to the axis of rotation of the yarn drum at least in a working position, wherein a first portion of a yarn located on the yarn drum is rewound onto the yarn drum, wherein the yarn balloon is defined by means of the first yarn guide surface, and a yarn withdrawal force of the yarn and/or a measurement value representing the yarn withdrawal force is detected.

Finally, the invention relates to a station of a yarn winding machine for rewinding a yarn from a pirn onto a winding bobbin by means of a yarn winding device, said station having a balloon defining device. During the rewinding process, the balloon defining device serves to define a yarn balloon formed between the spinning bobbin and the winding bobbin at least in the width direction, wherein the balloon defining device comprises a first balloon defining member with a first yarn guide surface having a first distance with respect to the rotation axis of the spinning bobbin at least in an operating position of the first balloon defining member. The workstation has at least one detection device for detecting a yarn withdrawal force of the yarn and/or a measurement value representing the yarn withdrawal force. And the workstation has a control device which is connected to the at least one detection device.

Background

The winding machine is used to rewind the yarn from a wound bobbin (e.g. from a ring spinning machine) onto a winding bobbin, thereby producing larger loops (so-called cross-laps (Kreuzspulen) in general). This is necessary for later further processing of the yarn, since the spinning cylinder generally contains less yarn. The winding machine has a plurality of winding stations at which the rewinding process is performed substantially independently of each other. During the rewinding process, the yarns of the individual bobbins are joined in succession by the splicer into a single continuous yarn. Furthermore, with the rewinding process, yarn flaws generated by the spinning machine upstream in the spinning process are removed from the yarn at the yarn winding machine by means of a yarn clearer.

During the rewinding from the bobbin to the winding bobbin, a yarn balloon is created between the unwinding position, in which the bobbin is located during the rewinding process, and the yarn guide arranged after the bobbin in the yarn running direction. This yarn balloon is formed by the centrifugal forces acting during the rewinding of the yarn from the spinning bobbin onto the yarn. The larger the radius of the yarn balloon during the rewinding process, the greater the yarn tension in the region of the yarn balloon. Numerous experiments have therefore been carried out to influence or define the yarn balloon in order to keep the yarn tension during the rewinding process as low as possible and thereby minimize the risk of yarn breakage times or adverse effects on the yarn quality.

A spinning machine with workstations each having a balloon limiting device is known from DE 10 2006 052 826 A1. The balloon-defining device can be adjusted in the vertical direction so that it can be displaced downwards following the unwinding progress of the spinning pirn during the winding process. The balloon defining device comprises a tube which continuously tracks in the vertical direction during the winding process corresponding to the position of the pirn cone, such that the radial distance of the tube with respect to the pirn cone remains approximately constant. In addition, the balloon-defining device comprises a second tube which is tracked in the vertical direction in dependence on the signal of the wire tension sensor. In this case, the so-called singles-yarn balloon (Einfach-fanenballoon) should also be set reliably at very high winding speeds during the entire winding process. The apparatus is relatively complex in construction. In addition, a relatively large wire tension may always be generated depending on the winding state of the pirn.

Disclosure of Invention

The object of the invention is therefore to provide a method for operating a workstation of a yarn winding machine, which makes it possible to carry out winding at a winding speed which is as constant as possible. In addition, a station of the yarn winding machine is also provided.

This object is achieved by a method and a workstation having the features of the independent claims.

In a method for operating a station of a yarn winding machine, a yarn is rewound onto a yarn winding bobbin from a pirn with the yarn winding bobbin by means of a yarn winding device, wherein during the rewinding process a yarn balloon formed between the yarn winding bobbin and the yarn winding bobbin is defined at least in the width direction by means of a balloon defining device. The balloon limiting device comprises at least one balloon limiting piece with a yarn guiding surface, which can be changed from a rest position to an operating position, wherein the yarn guiding surface has a certain distance relative to the rotation axis of the spinning tube in the operating position of the at least one balloon limiting piece. In this case, a first portion of the thread on the bobbin is rewound onto the bobbin, wherein a thread withdrawal force of the thread and/or a measurement value representing the thread withdrawal force is detected. It is proposed that, upon detection of an increase of the yarn withdrawal force by a predetermined value, the at least one balloon defining member of the balloon defining device is transferred from the rest position into the operating position and subsequently a second portion of the yarn on the bobbin is rewound onto the bobbin, wherein the yarn balloon is defined by means of the yarn guide surface.

The working position is here the position which the balloon-defining member occupies during rewinding and in which the balloon-defining member defines the balloon of the yarn. In contrast, the rest position is a position in which the balloon defining member does not define a yarn balloon. The rest position can be a pirn change position at the same time, which can enable the replacement of the empty spinning pirn with a fully wound pirn. However, it is also possible that the balloon defining member may be transferred into a pirn changing position different from the resting position.

In other respects, the axis of rotation is the central longitudinal axis of the spinning tube which is normally rotationally symmetrical. Also, during the rewinding process, no spinning of the bobbin occurs.

Likewise, the distance of the yarn guide surface from the axis of rotation is the smallest distance of the yarn guide surface from the axis of rotation. The thread guide surface can be formed cylindrically so that it overall has the same distance to the axis of rotation. The thread guide surface can however also be polygonal or irregularly shaped in some other way. In this case, the term "distance" relates to the smallest distance of the thread guide surfaces from the axis of rotation in each case.

In a second method for operating a workstation of a yarn winding machine, a first portion of a yarn located on a bobbin is rewound onto the bobbin, wherein a yarn withdrawal force of the yarn and/or a measurement value representing the yarn withdrawal force is detected, and wherein the yarn balloon is defined by means of the yarn guide surface. The thread guide surface of the at least one balloon-defining member is at a distance from the axis of rotation of the spinning tube at least during the rewinding of the first portion of the thread. In this second method, it is provided that, when an increase in the yarn withdrawal force by a predetermined value is detected, the distance of the yarn guide surface from the axis of rotation of the yarn drum is reduced and subsequently a second portion of the yarn located on the yarn drum is rewound onto the yarn drum, wherein the yarn balloon is defined by means of the yarn guide surface at a reduced distance from the axis of rotation.

In a third method, the balloon-defining device has a first balloon-defining piece with a first yarn guide surface, in which a first portion of the yarn located on the yarn drum is rewound onto the yarn drum, wherein the yarn balloon is defined by means of the first yarn guide surface, and wherein a yarn withdrawal force and/or a measurement value representing the yarn withdrawal force of the yarn is detected. The first yarn guide surface of the balloon defining member has a first distance relative to the rotational axis of the bobbin at least during rewinding of the first portion of the yarn. It is proposed that, when an increase in the yarn withdrawal force by a predetermined value is detected, a first distance of the first yarn guide surface from the axis of rotation of the yarn drum is reduced and subsequently a second portion of the yarn located on the yarn drum is rewound onto the yarn drum, wherein the yarn balloon is defined at a reduced distance from the axis of rotation by means of the first yarn guide surface.

Alternatively, in this third method, it is provided that, when an increase in the yarn withdrawal force by a predetermined value is detected, at least one second balloon defining piece of the balloon defining device with a second yarn guide surface, by means of which the yarn balloon is defined, is transferred from a rest position, in which the second balloon defining piece does not define the yarn balloon, into a working position, in which the second balloon defining piece defines the yarn balloon, and subsequently a second portion of the yarn located on the bobbin is rewound onto the bobbin.

For example, when the yarn withdrawal force is measured directly, an increase of a predetermined value is detected when the yarn withdrawal force increases by a predetermined absolute value or percentage value with respect to the initial value. In the case of an indirect measurement, for example by evaluating the position of the thread tensioner, an increase in the thread withdrawal force by a predetermined value can be detected by the thread tensioner advancing by a predetermined stroke or reaching a predetermined position. The predetermined value may be determined by an operator based on an empirical value, for example, and stored in the control device of the yarn winding machine. However, the predetermined value can also be obtained and determined by evaluating the past unwinding process during a self-learning process of the winding machine, in particular of the control device of the winding machine. It is also possible here that the winding machine only suggests the predetermined value and still has to be confirmed by the operator.

All three methods have in common that the action of the thread guide surface on the thread or the action of the thread guide surface on the thread is increased depending on the thread withdrawal force. This can be done by switching the balloon-defining element from the rest position into the operating position, or else by reducing the distance of the thread guide surface from the axis of rotation of the spinning cylinder. This effect is only produced if an increase in the thread withdrawal force requires an additional or increased effect of the thread guide surface. In this case, the winding can advantageously be carried out first without a defined balloon or with only one thread guide surface acting on the thread. By "activating" or "reinforcing" one or more yarn guide surfaces depending on the yarn tension, the yarn withdrawal force can thus be kept substantially constant during the winding process. The winding package can thereby be wound with a substantially constant winding tension, whereby loops of high quality can be produced. It is thereby also achieved that the winding takes place at a substantially constant, relatively high operating speed during the entire winding process. Thereby eliminating the need for the balloon defining means to be continuously and simultaneously guided with the pirn winding state as required in the prior art.

In this case, it is also possible within the scope of the invention to "activate" the additional thread guide surface or the additional balloon-limiting element several times during the rewinding process depending on the thread withdrawal force and/or to reduce the distance of one or more thread guide surfaces which have already acted on the thread several times depending on the thread withdrawal force.

Furthermore, a station of a yarn winding machine is proposed for rewinding a yarn from a pirn with a bobbin onto the bobbin by means of a yarn winding device. The station has a balloon defining device for defining a yarn balloon formed between the spinning bobbin and the winding bobbin at least in the width direction during the rewinding process. Wherein the balloon defining means comprises a first balloon defining member with a first yarn guiding surface having a first distance with respect to the axis of rotation of the spinning cylinder at least during rewinding. The workstation additionally has at least one detection device for detecting a yarn withdrawal force of the yarn and/or a measurement value representing the yarn withdrawal force. And the workstation has a control device which is connected to the at least one detection device. In the case of such a station, the control device is in connection with the balloon defining means. Depending on the signal of the at least one detection device, the first balloon-defining part of the balloon-defining device can be switched from a rest position, in which the first balloon-defining part does not define the balloon of the yarn, into an active position, in which the first balloon-defining part defines the balloon of the yarn.

Alternatively, it is provided in the case of such a station that the first distance of the first thread guiding surface relative to the axis of rotation of the spinning cylinder can be reduced as a function of the signal of the detection device.

According to a further embodiment, in the case of such stations, it is provided in addition to or instead of the two above-mentioned embodiments that the balloon-defining means comprise at least one second balloon-defining member with a second yarn-guiding surface, which can be transferred from the rest position into the operating position in dependence on the signal of the at least one detection means.

As already explained, in the case of such a station, the action of the yarn guide surface on the yarn can be "activated" one or more times during the rewinding process depending on the yarn withdrawal force, so that the yarn withdrawal force remains substantially constant during the winding process. Such a station also advantageously makes it possible to perform winding with a constant working speed. The station can thus be implemented in a constructionally simple and cost-effective manner, since it does not require the balloon defining device to continuously track the winding condition of the pirn.

Advantageously, in the method and apparatus according to the third embodiment, the second yarn guide surface has a second distance relative to the axis of rotation of the spinning cylinder in the operating position of the second balloon-defining member, the second distance being smaller than the first distance. The pirns from the ring spinning machine are generally unwound step by step, so that the yarn is gradually removed from the bobbin from top to bottom and the bobbin is exposed. Therefore, the yarn balloon is larger and larger when the yarn winding process is carried out. If the second guide surface has a smaller distance from the axis of rotation of the spinning cylinder than the first guide surface, the yarn loop can be advantageously tightened more strongly by the second guide surface than by the first guide surface.

It is also advantageous if, in order to detect an increase in the thread withdrawal force by a predetermined value, a limit value for the thread withdrawal force and/or for a measurement value representing the thread withdrawal force is determined, and if the limit value is exceeded, the respective balloon-defining member is switched into its operating position (a) and/or the distance to the respective thread guide surface is reduced. The limit value can be, for example, the absolute value of the measured yarn withdrawal force. Conversely, if the stroke of the thread-tensioning element is detected as a measurement value representing the thread withdrawal force, the limit value can also be defined by a certain position of the thread-tensioning element.

It is also advantageous if, in order to detect an increase in the yarn withdrawal force by a predetermined value, an allowable range of fluctuation of the yarn withdrawal force and/or of a measured value representing the yarn withdrawal force is determined, and if the range of fluctuation is exceeded, the balloon-defining member is switched into its operating position and/or the distance is reduced. The fluctuation range can be the permissible deviation of the yarn withdrawal force from the previously measured value. If the respective measured value leaves the determined tolerance band around this previously measured value, the respective balloon-defining element can be switched into its operating position or the distance from the respective thread guide surface can be reduced.

It is also advantageous if the thread withdrawal force is detected by means of a tension sensor, or if the at least one detection device is a tension sensor in the case of the station. Such tension sensors are generally present anyway at the working station, for example, in order to actuate the thread tensioner as a function of the thread withdrawal force. The tension sensor can then advantageously also be used to trigger the action of activating the thread guide surface.

However, it is also advantageous to detect the position and/or the adjustment travel of the tensioning element of the thread tensioner as a measurement value representing the thread withdrawal force. The thread take-up is generally actuated or adjusted as a function of the tension, i.e. it is opened further when the thread withdrawal force increases and closed further when the thread withdrawal force decreases. In any case, therefore, the position or forward adjustment travel of the tensioning element of the thread tensioner is a measurement representative of the thread withdrawal force and can be used to trigger the action of activating the thread guiding surface, as long as the thread tensioner has not reached its final position.

Correspondingly, it is advantageous to detect the position of the tensioning element by means of a proximity switch, in particular an optical sensor. In the case of the work station, it is likewise advantageous if the at least one detection device is a proximity switch, in particular an optical sensor. However, inductive, capacitive, magnetic or other proximity switches may naturally also be considered as an alternative.

Alternatively, it is advantageous in the case of the work station to detect the adjustment travel of the tensioning element by means of a travel sensor.

According to an alternative embodiment of the method, it is advantageous if the adjustment travel of the tensioning element can be detected by evaluating an adjustment value of the thread tensioner, in particular of the drive of the tensioning element, and/or by measuring a load value. The number of steps of the stepping motor can be detected, for example, when the thread tensioner is displaced by means of the stepping motor. The adjustment travel can likewise be determined from the current, voltage or other load values of the drive of the thread tensioner. In the case of the workstation, the control of the drive is then the at least one detection device.

It is also advantageous if the first balloon defining member and/or the at least one second balloon defining member is a balloon constricting ring. The balloon constricting toroid need not be circular, but may have a polygonal or other, even irregularly shaped, shape. The first and/or second balloon defining member may also be tubular in construction as well. The balloon defining member may be fully closed or have an opening. The balloon defining member may also be formed to be separable.

This is advantageous in the following cases: the first balloon-defining piece and/or the at least one second balloon-defining piece has at least two defining elements that are movable from a first position to a second position. The delimiting element can, for example, assume a first position in the rest position of the balloon delimiting element and a second position in the working position. It is also possible that the delimiting element occupies a first position in order to form a thread guiding surface with a first distance with respect to the axis of rotation of the spinning cylinder and that the delimiting element occupies a second position in order to form a thread guiding surface with a second distance with respect to the axis of rotation. It is also possible to envisage a number of limiting elements greater than two, which can form yarn guide surfaces of different diameters according to the type of flap.

It is also advantageous in the following cases: the first balloon defining member and/or the at least one second balloon defining member is transitionable into a pirn change position. The pirn changing position is in this case different from the resting position. It is however also possible that the resting position is also a pirn changing position at the same time. The switching of the first or second balloon defining member to the pirn changing position can in principle be performed in different ways. For example, it is contemplated that the separable balloon-cinching ring is opened until the pirn can be removed. Alternatively, the balloon defining member or the entire balloon defining means may be pivoted or linearly displaced in order to be transferred from the working or resting position to the pirn change position.

For example, it is advantageous if the station has a drive by means of which the first balloon-defining piece and/or the second balloon-defining piece can be displaced along a guide in the direction of the axis of rotation of the spinning tube. The balloon-defining member can then be transferred, for example, from a rest position or pirn-changing position above the spinning cylinder into a working position at the level of the spinning cylinder.

In particular in the case of a balloon limiting device with two balloon limiting members, it is advantageous if the first and the second balloon limiting members are displaceably supported at the guide member via a common carrier. The two balloon defining members can thus be transferred e.g. together into a pirn changing position above the pirn. It is likewise possible to switch at least one of the two balloon-limiting members or else to switch the two balloon-limiting members jointly into their operating position.

Drawings

Further advantages of the present invention are illustrated in the following examples. Wherein the method comprises the following steps:

FIG. 1 shows a front view of a yarn winding machine having a plurality of stations arranged alongside one another;

FIG. 2 shows a front view of a station of the yarn winding machine with a fully closed yarn tightener;

FIG. 3 shows the station of FIG. 2 with the tightener fully open;

figure 4 shows a detail view of a front view of the pirn and the air ring defining device at a first point in time at which the rewinding process starts, according to the first embodiment;

figure 5 shows a schematic view of the pirn and balloon defining device of figure 4 at a second point in time during the rewinding process;

figure 6 shows a schematic view of the pirn and balloon defining device of figure 4 at a third point in time during the rewinding process;

figure 7 shows a detailed view of a front view of the pirn and the air-ring defining device according to a second embodiment at a first point in time when the rewinding process starts;

figure 8 shows a schematic view of the pirn and balloon defining device of figure 7 at a second point in time during the rewinding process;

figure 9 shows a schematic view of the pirn and balloon defining device of figure 7 at a third point in time during the rewinding process;

fig. 10 shows a schematic representation of the yarn withdrawal force and the limit value of the yarn withdrawal force during the yarn winding process;

fig. 11 shows a schematic illustration of the yarn withdrawal force and the fluctuation range of the yarn withdrawal force during the yarn winding process;

FIG. 12 shows a detailed representation of the thread tensioner in a front view and the detection of the adjustment stroke of the thread tensioner;

fig. 13 shows a balloon defining piece with two defining elements in a resting position in top view;

FIG. 14 shows the balloon defining member of FIG. 12 in an operating position;

FIG. 15 shows a balloon defining member having two defining elements in a first position in a top view; and

figure 16 shows the balloon defining member of figure 15 with two defining elements in a second position.

Detailed Description

In the following description of the exemplary embodiments, identical or at least similar features of similar design and/or mode of action are provided with the same reference signs. Furthermore, these reference numerals are explained in detail only at the time of the first time, and only the differences from the already described embodiments are explained in the following embodiments. Moreover, for the sake of clarity, only one or a few of the plurality of identical components or features are generally labeled.

Fig. 1 shows a front view of the yarn winding machine 1. The yarn winding machine 1 has a plurality of stations 2 arranged side by side, said stations being arranged between two frames 21, only one of which is shown here. The station 2 is formed to unwind the yarn 3 from the pirn 22 with the bobbin 4 and to wind it onto the bobbin 6 by means of the yarn winding device 5. The working position 2 has a plurality of working mechanisms for this purpose. The working mechanism comprises a splicer 16 for connecting the yarn end of the spinning bobbin side to the yarn end of the winding bobbin side after the yarn is broken, the yarn is cut off or the spinning bobbin 4 is idle, a movable suction nozzle for finding the yarn end of the winding bobbin side and a movable suction nozzle 20 for finding the yarn end of the spinning bobbin layer. In addition, the station has a clearer 12.

The winding machine 1 has a central control device 13 which controls the processes carried out at the winding machine 1. In addition, as shown in the present case, each of these workstations 2 can also have its own control device 13, which is connected to the central control device 13 and controls the processes carried out at the respective workstation 2.

The yarn 3 wound on the spinning cylinder 4 is drawn off from the spinning cylinder 4 and passes through the balloon-defining piece 23, the yarn guide 15 and the yarn tightener 7, which applies an adjustable yarn withdrawal force to the running yarn 3 (see fig. 10 and 11). For this purpose, the thread tensioner 7 can be actuated correspondingly by the control device 13 of the winding position 2. In order to measure the thread withdrawal force, a tension sensor 10 is arranged in the present case in the vicinity of the winding bobbin 6. The thread take-off force is set by the thread take-off device 7 and is adjusted as a function of the measured thread take-off force.

The thread tensioner 7 is now explained in detail with the aid of fig. 2 and 3. Fig. 2 shows the station 2 in a front view. The gripper 7 is shown here in the closed position GP. In the normal winding mode of operation, the thread tensioner 7 assumes a partially closed position, so that the thread 3 is deflected several times at the thread tensioner 7 and is thus subjected to frictional forces. By further opening or further closing the thread tensioner 7, the thread withdrawal force can be influenced. The thread tensioner 7 shown in the present case is formed as a rake thread tensioner and has two tensioning elements 8 which can be moved relative to one another by means of a drive 9. In this case, only one of the two tensioning elements 8 can be moved, or, as currently shown, both tensioning elements 8 can be moved. In addition, a yarn balloon 14 formed between the spinning cylinder 4 and the yarn winding cylinder 6 during the rewinding process is also shown in this illustration.

In contrast, fig. 3 shows the gripper 7 in a fully open position OP, in which the thread 3 passes freely and without contact through the gripper 7. Accordingly, in this position, no tension is applied to the yarn 3.

By means of the thread tensioner 7, the thread withdrawal force can be adjusted and kept substantially constant in another region of the winding process. However, once the thread tensioner 7 has reached the fully open position OP or the closed position GP or the tensioning element 8 has reached its final position, the thread withdrawal force can no longer be influenced by means of the thread tensioner 7. Therefore, in order to keep the yarn withdrawal force low, it is proposed to influence the shape and size of the yarn balloon 14 in accordance with the yarn withdrawal force by means of the balloon-defining device 18 (see fig. 4).

Fig. 4 shows a first embodiment of the balloon defining device 18 and the pirn 22 with the spinning cylinder 4. The balloon defining means 18 has

balloon defining members

23, 26, which in the present case are formed as balloon constricting rings. The

balloon defining pieces

23, 26 have yarn guiding surfaces 24, 27 with a distance a1, a2 with respect to the axis of rotation 25 of the pirn 22 or the spinning cylinder 4. As can also be gathered from fig. 4, the balloon delimiting means 18 is in connection with the control device 13, as is indicated by means of a dashed line. The control device 13 is in turn connected to a detection device 17, which detects the yarn withdrawal force or a measurement value representing the yarn withdrawal force. Fig. 4 here shows the station 2 or quill 22 at the beginning of the rewinding process. The spinning cylinder 4 is not completely wound at this point in time. The yarn balloon 14 thus formed has only a relatively small height and a relatively small width at this point in time. The

balloon defining pieces

23, 26 are in the present case positioned fixedly in terms of their height relative to the spinning cylinder 4 during the entire rewinding process, i.e. not displaced along the axis of rotation 25.

Fig. 5 shows the pirn 22 or station 2 of fig. 4 after a portion of the yarn 3 wound on the bobbin 4 has been unwound, at another point of time of the rewinding process. Here, it can be seen that the yarn is gradually removed from the spinning bobbin 4 from top to bottom during unwinding and thus the upper pirn cone is displaced further downwards. The yarn balloon has thus become larger, so that now the yarn guide surfaces 24, 27 act on the yarn 3 and the yarn balloon 14 is defined in the width direction. This produces a double balloon, thereby reducing the centrifugal force in the yarn balloon 14 and thus also the yarn withdrawal force. The first part of the thread 3 located on the spinning cylinder 4 is now unwound, wherein the thread loop 14 is defined by means of the thread guide surfaces 24, 27.

However, even if this is defined by the thread guide surfaces 24, 27, an increase in the thread withdrawal force occurs mainly in the latter half of the rewinding process. If an increase by a predetermined value is detected by the detection means 17, the distance a1, a2 of the thread guiding surfaces 24, 27 with respect to the axis of rotation 25 is reduced on the basis of this signal from the detection means 17.

Fig. 6 shows a schematic view of the pirn 22 and the air ring defining means 18 of fig. 4 and 5 at a third point in time just reducing the distances a1, a2 of the yarn guiding surfaces 24, 27 with respect to the rotation axis 25. At this point, the second part of the thread 3 is unwound from the bobbin 4, wherein the thread guide surfaces 24, 27 now act on the thread balloon 14 at reduced distances a1, a2. The yarn balloon 14 now becomes higher following the winding state of the spinning cylinder 4, but now a further widening in the width direction is counteracted thereby, so that the yarn balloon 14 is now defined by the yarn guiding surfaces 24, 27, which are retracted to a smaller distance a1, a2.

The reduction of the distance a1, a2 of the thread guide surfaces 24, 27 can be effected, for example, in the following manner: the two or more delimiting elements 29 of the

balloon delimiting members

23, 26 are moved from the first position I to the second position II, as will be explained later on with the aid of fig. 15 and 16.

Figure 7 shows a second embodiment of the balloon defining means 18. This embodiment has a first balloon defining member 23, which is also formed as a balloon-tightening ring and has a yarn guiding surface 24 having a distance a1 with respect to the rotation axis 25 of the cop 22 or the spinning bobbin 4. The balloon defining means 18 furthermore have a second balloon defining member 26 with a second yarn guide surface 27. The second balloon defining member 26 is transitionable from the rest position R shown in fig. 7 and 8 to the working position a shown in fig. 9. Here, too, the balloon limiting device 18 is in connection with the control device 13, as is indicated by a dot-dash line. Fig. 7 here again shows the pirn 22 at the beginning of the rewinding process, when the bobbin has not finished being wound.

Fig. 8 shows the pirn 22 or station 2 of fig. 7, now during the unwinding of the first portion of yarn 3 to be wound on the bobbin 4, wherein the yarn guide surface 24 of the first balloon defining member 23 acts on the yarn 3 and the yarn balloon 14 is defined in width direction. The second balloon defining member 26 is still in its rest position R. In order to switch the second balloon defining member 26 into its operating position a (see fig. 9), the defining element 29 (see fig. 13-16) can be switched again from the first position I into the second position II. In the present example, this is done by pivoting the delimiting element 29 by 90 °. The balloon defining members 26 are thereby formed as separable balloon constricting rings.

Finally, fig. 9 shows a schematic view of the pirn 22 and the air-ring defining device 18 of fig. 7 and 8 at the point in time just after the increase of the yarn extraction force is detected by the detection device 17. Based on the signal of the detection device 17, the balloon defining device 18 is actuated again by the control device 13 and the balloon defining member 26 is transferred from its rest position R into its operating position a. In the operating position a, the second yarn guide surface 27 has a distance a2 relative to the axis of rotation 25, which in the present case is less than the distance a1 of the first yarn guide surface 24 relative to the axis of rotation 25. A second portion of the thread 3 is now unwound from the bobbin 4, wherein the second thread guide surface 27 acts on and delimits the thread balloon 14 by a second distance a2.

Unlike the embodiments shown in fig. 7-9, the distance a2 of the second balloon defining member 26 relative to the axis of rotation 25 does not necessarily have to be less than the distance a1 of the first balloon defining member 23. It is also conceivable for the first guide surface 24 and the second guide surface 27 to act simultaneously on and define the yarn balloon 14. Depending on the distance of the two balloon-defining

members

23, 26 relative to each other, multiple balloons are formed in this case.

In addition, in contrast to the illustrations in fig. 7 to 9, it is also possible for the balloon limiting device 18 to have, as in fig. 4 to 6, only a single

balloon limiting member

23, 26 which can be switched from the rest position R into the operating position a. The balloon-defining member can then likewise be transferred from the rest position R into the working position a on the basis of a signal from the detection device 17 (see fig. 10 and 11) that the yarn withdrawal force has increased.

It is also possible to combine in the balloon-defining means 18 a plurality of balloon-defining

members

23, 26 which successively or partly simultaneously switch from their rest position R into their working position a upon detection of an increase in the yarn withdrawal force, or respectively reduce the distances a1, a2 relative to the axis of rotation 25 upon detection of an increase in the yarn withdrawal force. The different embodiments of the

balloon defining members

23, 26 can also be combined in a single balloon defining means 18.

In order to trigger the transition from the rest position R into the working position a and/or the reduction of the distances a1, a2, respectively, a limit value 28 can be preset for the thread withdrawal force, for example. This is shown in fig. 10.

Finally, it is also possible for the two balloon-defining

pieces

23, 26 or also the other balloon-defining

pieces

23, 26 to be arranged jointly in a height-adjustable manner at the station 2. For this purpose, the

balloon delimiting members

23, 26 may be arranged, for example, on a common carrier which is displaceably and drivably supported on guides extending in the direction of the axis of rotation 25. The

balloon defining members

23, 26 can here be arranged in a constant height relative to the spinning bobbin 4 during the rewinding process, but can nevertheless be displaced into a pirn changing position above the spinning bobbin in order to take out the spinning bobbin 4 which is idle and to change it to a fully wound spinning bobbin 4.

Fig. 10 shows the curve of the yarn withdrawal force over the entire rewinding process or run length of the yarn (as would have been run without the influence of the balloon). It can be seen here that the yarn withdrawal force is substantially constant in the first half of the rewinding process, while it increases in the latter half. It can also be seen that the yarn withdrawal force increases exponentially at the end of the rewinding process, in particular in the last third. Since small fluctuations in the yarn withdrawal force do not cause problems and can generally still be compensated for by the yarn tightener 7, the limit value 28 can, for example, assume a value which is 20% higher than the value of the yarn withdrawal force in the first half of the rewinding process.

Alternatively, it is also possible to use the fluctuation range 30 as a trigger signal instead of the limit value 28 being exceeded. This is shown in fig. 11.

Since it is not problematic that the yarn withdrawal force fluctuates only slightly, it can be determined that, for example, a fluctuation range 30 of 5 to 10N is permissible within a certain comparison period. The thread withdrawal force is continuously detected and compared with the previously measured values of the comparison period. If the permissible fluctuation range 30 is exceeded, as shown in fig. 11, this is detected by the detection means 17 and a signal is output to the control device 13. The control device 13 can then actuate the balloon defining means 18 on the basis of this signal in order to effect the additional

balloon defining pieces

23, 26 or to reduce the distances a1, a2 of the thread guiding surfaces 24, 27 relative to the axis of rotation 25.

Alternatively, it is also possible to measure a measurement value representing the yarn withdrawal force instead of directly measuring the yarn withdrawal force. This is shown in fig. 12.

Fig. 12 shows a detail view of the thread tensioner 7 with two tensioning elements 8 which can be moved by means of the drive 9. As already mentioned in the opening paragraph, the drive 9 is actuated on the basis of the signal of the tension sensor 10, which measures the thread withdrawal force. It is therefore shown here by way of example that the current adjustment travel s of the tensioning element 8, which is located on the right in the figure, or the current position of the tensioning element 8 corresponds to an indirect characteristic value of the yarn withdrawal force.

In the present example, it is detected by means of the sensor 11 whether the tensioning element 8 is in its fully open position OP. The closed position GP of the thread tensioner 7 is also shown in chain line. However, the advanced adjustment travel s can also be detected by means of a travel sensor.

Fig. 13 and 14 finally also show a

balloon delimiting member

23, 26 with two delimiting elements 29 which can be moved from a first position I, illustrated in fig. 13, to a second position II, illustrated in fig. 14. The two limiting elements 29 are pivotably supported for this purpose (in the present case, however, they are shown in an exploded manner). In the present example, the

balloon defining members

23, 26 are located in the rest position R when the defining element 29 occupies the first position I. In the rest position R, the

balloon defining members

23, 26 do not define the yarn balloon 14. Since in this rest position R the delimiting element 29 is outwardly distanced from the periphery of the pirn 22, the rest position R can simultaneously be used as pirn changing position.

In contrast, in the operating position a of the

balloon defining members

23, 26 illustrated in fig. 14, the defining element 29 occupies the second position II. In this position, the delimiting element 29 forms a closed balloon-tightening ring and can delimit the yarn balloon 14.

As can be further appreciated from fig. 14, since the

balloon defining members

23, 26 have the rest position R, it is also possible that the diameter of the yarn guiding surfaces 24, 27 of the

balloon defining members

23, 26 is smaller than the outer diameter of the pirn 22. If this is the case, the balloon-defining

pieces

23, 26 can only be displaced into their working position a if at least the upper part of the spinning cylinder 24 has been exposed.

In contrast, fig. 15 and 16 show a further embodiment of the

balloon defining members

23, 26 with a defining element 29 which can be moved from the first position I to the second position II. Such an embodiment of the

balloon defining members

23, 26 can advantageously be used to reduce the distance a1, a2 of the yarn guiding surfaces 24, 27 with respect to the rotation axis 25 of the pirn 22 or to reduce the inner dimension (here the inner diameter) of the yarn guiding surfaces 24, 27. In fig. 15, the limiting element 29 is in a first position I, in which the thread guide surfaces 24, 27 form a larger diameter. In contrast, in fig. 16, the limiting element 29 is in the second position II, in which the thread guide surfaces 24, 27 are constricted and therefore have a smaller diameter and thus also a reduced distance a1, a2 relative to the axis of rotation 25. The distances a1, a2 and the axis of rotation 25 can be seen in fig. 4-6, but are not shown in fig. 15 and 16.

In the figures described herein, the respective

balloon defining members

23, 26 are arranged to be transferred from the rest position R into the working position a so that the movable defining element 29 moves from the first position I to the second position II. However, it is also possible that one or more

balloon defining members

23, 26 are arranged at the station 2 in a manner movable together, for example along the rotation axis 25, in order to be transferred from their rest position R, for example arranged in the vicinity of the yarn guide 15 (see fig. 2-9) above the pirn 22, into their working position a.

The invention is not limited to the embodiments shown and described. Modifications are also possible within the scope of the claims, as are any combination of the features described, even if these features are shown and described in different parts of the description or claims or in different embodiments, provided that they do not conflict with the teachings of the independent claims.

List of reference numerals

1. Yarn winding machine

2. Work station

3. Yarn

4. Spinning tube

5. Yarn winding device

6. Yarn winding drum

7. Yarn tightening device

8. Tensioning element

9. Drive for a tensioning element

10. Tension sensor

11. Sensor with a sensor element

12. Yarn cleaner

13. Control device

14. Yarn balloon

15. Yarn guide

16. Splicing device

17. Detection device

18. Balloon limiting device

19. Air suction nozzle

20. Suction tube

21. Frame structure

22. Pirn

23. A first air ring limiting piece

24. The first yarn guide surface

25. Axis of rotation

26. A second balloon defining member

27. Second yarn guide surface

28. Limit value

29. Limiting element

30. Pivoting range

A working position

R rest position

a1 First distance

a2 Second distance

s regulating the path

I first position

II second position

GP yarn tightening device closing position

Open position of OP yarn tightener

Claims

1. A method for operating a station (2) of a yarn winding machine (1), the method comprising:

rewinding the yarn (3) onto the winding bobbin (6) from the pirn (22) with the spinning bobbin (4) by means of the winding device (5);

-defining a yarn balloon (14) formed between the spinning bobbin (4) and the winding bobbin (6) at least in the width direction by means of a balloon defining device (18) during the rewinding process;

wherein the balloon defining means (18) comprise at least one balloon defining piece (23, 26) with a thread guiding surface (24, 27) which can be transferred from a rest position (R) to a working position (A);

rewinding a first portion of the yarn (3) on the bobbin (4) onto the bobbin (6), detecting a yarn withdrawal force of the yarn (3) and/or a measurement value representative thereof, wherein the yarn guide surface (24, 27) has a distance (a 1, a 2) with respect to the rotation axis (25) of the bobbin (4) in the working position of the at least one balloon defining member (23, 26);

characterized in that, upon detection of an increase of the yarn withdrawal force by a predetermined value, the at least one balloon defining member (23, 26) of the balloon defining means (18) is transferred from the rest position (R) to the working position (A) and subsequently a second portion of the yarn (3) located on the bobbin (4) is rewound onto the bobbin (6), wherein the yarn balloon (14) is defined by means of the yarn guiding surfaces (24, 27).

2. A method for operating a station (2) of a yarn winding machine (1), the method comprising:

rewinding the yarn (3) onto the winding bobbin (6) by means of the winding device (5) from the pirn (22) with the spinning bobbin (4);

wherein the balloon defining means (18) comprise at least one balloon defining piece (23, 26) with a thread guiding surface (24, 27);

rewinding a first portion of the yarn (3) on the bobbin (4) onto the bobbin (6), detecting the yarn withdrawal force of the yarn (3) and/or a measurement value representative thereof;

-defining the yarn balloon (14) by means of the yarn guiding surface (24, 27) during rewinding of a first portion of the yarn (3), and-at least at the beginning of rewinding-the yarn guiding surface (24, 27) has a distance (a 1, a 2) with respect to the axis of rotation (25) of the spinning drum (4);

characterized in that, upon detection of an increase of the yarn withdrawal force by a predetermined value, the distance (a 1, a 2) of the yarn guide surface (24, 27) relative to the axis of rotation (25) of the spinning bobbin (4) is reduced and subsequently a second portion of the yarn (3) lying on the spinning bobbin (4) is rewound onto the winding bobbin (6), wherein the yarn balloon (14) is defined by means of the reduced distance (a 1, a 2) of the yarn guide surface (24, 27) relative to the axis of rotation (25).

3. A method for operating a station (2) of a yarn winding machine (1), the method comprising:

wherein the balloon-defining means (18) comprise a first balloon-defining piece (23) with a first yarn guide surface (24);

rewinding a first portion of the yarn (3) on the bobbin (4) onto the bobbin (6), wherein the yarn balloon (14) is defined by means of the first yarn guiding surface (24), and detecting a yarn withdrawal force of the yarn (3) and/or a measurement value representative thereof, wherein the first yarn guiding surface (24) of the balloon defining member (23) has a first distance (a 1) with respect to a rotation axis (25) of the bobbin (4) at least during rewinding of the first portion of the yarn (3);

characterized in that, upon detection of an increase of the yarn withdrawal force by a predetermined value, a first distance (a 1) of the first yarn guide surface (24) with respect to the axis of rotation (25) of the bobbin (4) is reduced and subsequently a second portion of the yarn (3) located on the bobbin (4) is rewound onto the bobbin (6), wherein the yarn balloon (14) is defined by means of the first yarn guide surface (27) at the reduced distance (a 1) with respect to the axis of rotation (25);

and/or switching at least one second balloon defining piece (26) of the balloon defining device (18) with a second yarn guiding surface (27) from a rest position (R) into a working position (A) and subsequently rewinding a second part of the yarn (3) located on the spinning bobbin (4) onto the winding bobbin (6), wherein the yarn balloon (14) is defined by means of the second yarn guiding surface (27).

4. The method according to the preceding claim, characterized in that in the operating position (a) of the second balloon defining member (26), the second yarn guiding surface (27) has a second distance (a 2) with respect to the rotation axis (25) of the spinning tube (4), which is smaller than the first distance (a 1).

5. The method of any one of the preceding claims, further comprising: a limit value (28) for the yarn withdrawal force and/or a measurement value representing the yarn withdrawal force is determined, and the balloon defining member (23, 26) is transferred into its working position (a) and/or the distance (a 1, a 2) is reduced when the limit value (28) is exceeded.

6. The method of any one of the preceding claims, further comprising: determining an allowable fluctuation range (30) of the yarn withdrawal force and/or of a measurement value representing the yarn withdrawal force, and switching the balloon-defining member (23, 26) into its working position (A) and/or reducing the distance (a 1, a 2) when the fluctuation range (30) is exceeded.

7. Method according to any of the preceding claims, characterized in that the yarn withdrawal force is detected by means of a tension sensor (10).

8. Method according to any of the preceding claims, characterized in that the position and/or the adjustment stroke(s) of the tensioning element (8) of the thread tensioner (7) is detected for use as a measurement value representing the thread withdrawal force.

9. Method according to any one of the preceding claims, characterized in that the adjustment travel(s) of the tensioning element (8) is detected by analyzing the adjustment value of the tightener (7), in particular of the drive (9) of the tensioning element (8), and/or by measuring a load value.

10. A station (2) of a yarn winding machine (1) for rewinding a yarn (3) from a pirn (22) with a bobbin (4) onto a yarn winding bobbin (6) by means of a yarn winding device (5);

said station having a balloon-defining device (18) for defining, at least in the width direction, a yarn balloon (14) formed between the spinning cylinder (4) and the winding cylinder (6) during the rewinding process, wherein the balloon-defining device (18) comprises a first balloon-defining piece (23) with a first yarn guide surface (24);

at least during rewinding, the first thread guiding surface has a first distance (a 1) with respect to the axis of rotation (25) of the bobbin (4);

the workstation comprises at least one detection device (17) for detecting a yarn withdrawal force of the yarn (3) and/or a measurement value representing the yarn withdrawal force;

and having a control unit (13) which is connected to the at least one detection device (17);

characterized in that the control unit (13) is in connection with the balloon defining device (18) and the first balloon defining piece (23) of the balloon defining device (18) can be switched from a rest position (R) into a working position (A) in dependence on the signal of the at least one detection device (17) or can reduce the first distance (a 1) of the first yarn guiding surface (24) relative to the rotation axis (25) of the spinning tube (4) in dependence on the signal of the at least one detection device (17);

and/or the balloon defining means (18) comprise at least one second balloon defining piece (26) with a second yarn guiding surface (27), the second balloon defining piece (26) being capable of being switched from the rest position (R) into the working position (A) in dependence on a signal of the at least one detection means (17).

11. Station (2) according to the preceding claim, wherein in the working position (a) of the at least one second balloon-defining member (26) the second guide surface (27) has a second distance (a 2) with respect to the rotation axis (25) of the spinning cylinder (4), which is smaller than the first distance (a 1).

12. Station (2) according to any one of the preceding product claims, wherein said at least one detection device (17) is a tension sensor (10).

13. Station (2) according to any one of the preceding product claims, wherein said at least one detection device (17) is a proximity switch, or a distance sensor, or an identification sensor, preferably an optical sensor (11).

14. Station (2) according to any one of the preceding product claims, wherein said at least one detection device (17) is a travel sensor (11).

15. Station (2) according to any one of the preceding product claims, wherein said at least one detection device (17) is a controller of the drive (9).

16. Station (2) according to any one of the preceding product claims, wherein the first balloon-defining member (23) and/or the at least one second balloon-defining member (26) is a balloon-tightening ring.

17. Station (2) according to any one of the preceding product claims, wherein the first balloon-defining member (23) and/or the at least one second balloon-defining member (26) has at least two defining elements (29) which are movable from a first position (I) to a second position (II).

18. Station (2) according to any of the preceding product claims, wherein the first balloon-defining member (23) and/or the at least one second balloon-defining member are transitionable into a pirn-change position.